Concrete block molding apparatus



Nov. 8, 1960 .1. F. HARRIS CONCRETE BLOCK MOLDING APPARATUS P1 1 Z55/411A E fi@ Filed May 8, 1959 2516 157/1 INVENToR. JP/Mfs I.' #mM/.5,

MJ 7mm/115.

PIEi Unite This invention relates generally to concreteblock molding apparatus, and in particular to an improved means for insuring a uniform distribution of aggregate over the mold box. v y

Conventionally, in the molding of concrete blocks,

power operated apparatus feeds somewhat moist aggregate into the open top of a mold box which is divided into multiple compartments, each acting as a mold fora single block. The mold is vibrated for a predetermined time period'with the aggregate being held under pressure, after which the formed block is ejected or removed from the mold by a stripping head. Since the feed time and vibrating or nish time for the mold represent a substantial portion of the total time period required to manufacture the blocks, economy of manufacture can be greatly enhanced by shortening the feed time and vibrating or iinish time inherent in the process.

` The present invention provides apertured bars which are resiliently mounted over the mold box division plates, the apertures and the resilient mounting combining to distribute the aggregate rapidly and uniformly over the mold box. The presence of the apertured bars further serves to confine a maximum amount of material (aggregate and cement mix) over each compartment ofthe mold during the feeding process.

It is, therefore, the primary object of the present invention to provide apparatus for concrete block molding, the use of which permits the feed time and finish time for the mold to be reduced to a minimum While maintaining the desired density of the block.

A further object of the present invention is to provide apparatus of the type referred to which eliminates the necessity for conventional agitator grids and the shutdown period resulting from their frequent clogging.

A further object of the present invention is to provide apparatus of the type referred to which permits the aggregate to be uniformly and rapidly distributed over the mold box during its vibratory period.

A further object of the present invention is to provide a resilient mounting for apertured bars used in block molding apparatus whereby the plates are prevented from fatiguing and breaking at their area of attachment to the mold box.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

Fig. 1 is a perspective view of a mold box having the apparatus of the present invention incorporated thereon.

Fig. 2 is a side sectional View of the mold box of Fig. 1.

Fig. 3 is a sectional, side view of the apertured core vsupporting bar.

Fig. 4 is a fragmentary View of a modified form of 'the apertured core support bar or plate.

Fig. 5 is a view similar to Fig. 4, but showing a modified form of the core bar.

Fig. 6 is a View similar to Fig. 4, but showing a further modiiied form of the core bar.

ttes Paf() Fig. 7 is a view similar to Fig. 4, but showing a further modified form of the core bar.

Fig. 8 is a view similar to Fig. 4, but showing a further modified form of the core bar.

Fig. 9 is a view similar to Fig. 4, but showing a further modied form of the core bar.

Referring initially to Figs. l, 2 and 3 there is shown at 10 a mold box having side bars 11. Bolted to the side bars 11 is a top plate 12 which has an upturned marginal portion along three of its sides to provide a mold fence 13..

'I'he mold box is provided with outer division plates 141 and inner division plates 16 which are rigidly mountedv so as to span the side bars and divide the mold box into a plurality of compartments.

Bisecting each of the compartments thus formed aref core bars 17 which carry depending cores 18 extending: into the mold box. At their ends each of the core barshas a depending portion 17a which extends through appropriately positioned slots in the top plate. The tips of the depending portions 17a iit into slots in yokes 19 and rivets 21, passing through the slots, hold the portions 17a in the yoke slots. The yokes 19 may be drawn down toward an outwardly flanged portion 11a of the side bars by means of tighten-down bolts 22.

The central portion of the mold box rests upon a pallet 23 and depending portions 24 of the side bars accommodate vibrator shafts 26 and Vibrator sheaves 27. Actuation of the vibrator shafts during the block molding process serves to vibrate the mold box and its contents at a relatively high frequency. The apparatus so far described is conventional. y

The apertured feed bars 28- overlie the upper margins of the division plates and extend in the same plane. As may best be seen in Figs. 2 and 3, each of the bars 28 has depending portions 28a at each of its ends, the portions 28a extending freely through slots 29 in the topplate 12. The apertured bars are retained in position by a resilient mounting means which includes rubber pads 311 positioned on each side of the portions 28a and held in place by means of bolts 32. The central portion of each of the bars 28 is provided with spaced, circular apertures 33 whose margins may be inwardly beveled to provide a somewhat sharpened edge defining the apertures.

As previously mentioned, with the mold box conventionally in position on a pallet or support surface 23, somewhat moist aggregate may be fed into the open top of the mold box. This aggregate may take the form of a mixture of sand, gravel, cinders or Haydite with cement, the moistened aggregate forming concrete under conventional curing conditions. The core box is filled with aggregate to a level above the division plates 16. The ag gregate is then placed under compression and, in Conventional practice, the mold box is vibrated at a relatively high frequency so that the aggregate may be compacted into the mold.

One of the primary advantages resulting from the use of the apertured bars 28 embodying the present invention is the confining of a maximum amount of material over each mold compartment and the even and rapid distribution of aggregate, during the vibrating period, over each compartment of the mold box. This uniform and rapid distribution of the aggregate occurs because of the presence of the apertures 33 which permit the aggregate to migrate across each compartment while yet performing their aggregate confining function. The somewhat resilient mounting for the bars 28 provided by the rubber pads 31 permits the apertured bars to vibrate somewhat out of synchronism with the mold box, and this further appears to aid the movement of the aggregate over the mold compartments. The somewhat resilient mounting for the core bars has the further advantage of prolonging the service life of` the core bars, since, with this resilient mounting, they are less likely to fatigue and break at their point of junction with the mold box.

Figs. 4-9 illustrate various forms which the apertures or aggregate passages 3 3 in the core barsZ may take. Each of these possible modifications of the bars 28 appears to provide the desired aggregate distribution over the mold box during the vibrating operation. It willbe understood that While circular apertures having beveled margins are shown in Figs. 2 and 3, the present invention is not to be limited to this specific form for the apertures.

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modiications may readily suggest themselves to persons skilled in this art and within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

l. A mold box assembly for forming structural block from aggregate comprising an open-top mold box having an outwardly anged upper margin, division plates separating said box into parallel, block-molding compartments, feed bars having a central portion extending vertically above the upper margin of said box and aligned with said division plates, the opposite ends of said feed bars having depending portions extending through the anged margin of said box and downwardly along the outer face of the sides of the box, means for resiliently retaining said feed bars in position comprising rubber pads secured on opposite sides of said depending bar portions and below the flanged margin of the box, the central portion of said feed bars having a series of apertures therein, and means for vibrating said mold box.

2. A mold box assembly for forming structural block from aggregate comprising an open-top mold box having an outwardly flanged upper margin, division plates separating said box into parallel, block-molding compartments, feed bars having a central portion extending above the upper margin of said box, the opposite ends of said feed bars having depending portions extending through the anged margin of said box and downwardly along the outer face of the sides of the box, means for resiliently retaining said feed bars in position, the central portion of said feed bars having a series of apertures therein, and means for vibrating said mold box.

3. A mold box assembly for forming structural block from aggregate comprising an open-top mold box, division plates Separating said box into block-molding compartments, feed bars having a central portion extending vertically above the upper margin of said box and aligned with said division plates, means for resiliently retaining said feed bars in position, the central portion of saidfeed bars having a series of apertures therein, and means for vibrating said mold box.

4. A mold box assembly for forming structural block from aggregate comprising an open-top mold box, division plates separating said box into parallel, blockmolding compartments, feed bars having a central portion extending vertically above the upper margin of said box and aligned with said division plates, means for resiliently retaining said feed bars in position, the central portion of said feed bars having a series of apertures therein, said feed bars having bevelled portions terminating in sharp edges defining said apertures and means for vibrating said mold box.

References Cited in the file of this patent UNITED STATES PATENTS 2,191,578 Money Feb. 27, 1940. 

